This invention relates to a fermentative process for producing D-arabitol having the empirical formula C.sub.5 H.sub.12 O.sub.5.
In fermentation processes for preparing D-arabitol known hitherto, yeasts of the genera Candida, Saccharomyces, Hansenula, Debaryomyces, Torulopsis, Pichia or Endomycopsis are used, and nutrient media containing carbohydrates such as glucose, sucrose or glycerol, as the principal carbon source are employed. These known processes have various disadvantages, however. The substances such as glucose, glycerol and sucrose, employed as nutrient media are expensive. Furthermore, it is very difficult to separate the D-arabitol formed in these processes from the sugars used as the carbon source.
A process is known for preparing D-arabitol by cultivating a yeast of the genus Candida or Torulopsis, in which relatively inexpensive starting materials, such as hydrocarbons or ethyl alcohol, are employed in the nutrient media as the main carbon source (Agricultural and Biological Chemistry, Volume 38, 1875-1888, 1974). This article reports, however, that the yeast Pichia membranfaciens in a nutrient medium containing hydrocarbons as the principal carbon source produces no D-arabitol at all. It has also been established experimentally that other micro-organisms of the genus Pichia, for example P. fluxnum, P. fermentans and P. toletana, do not produce any D-arabitol in culture media containing hydrocarbons.
In the present invention, it has surprisingly been found that a specific species of Pichia, namely Pichia haplophila, and mutants derived therefrom fermentatively produce D-arabitol in high yields from inexpensive hydrocarbons or ethyl alcohol.
The arabitol thus obtained by the process of the present invention can advantageously be separated in a simple manner from the culture liquor.